Charles ralph townsend and joseph george skinner



C R. TOWNSEND AND J. G. SKINNER.

CLAMPING DOG.

APPLICATION FILED JUNE 13. 191B.

Patented Dec. 30, 1919.

Wemsqs/K CHARLES RALPH TOWNSEND AND JOSEPH GEORGE SKINNER, 0FBIRMINGHAM,

ENGLAND.

GLAMIF'ING-IDO G.

Specification of Letters Patent.

Patented Dec. 30, 1919.

Application filed June 13, 1918. Serial No. 239,906.

To all whom it may concern:

Be it known that we, CHARLEs RALPH TOWNSEND and JosEPH GEORGE SKINNER,subjects of the Kin of Great Britain, residing at Caxton House, GreatCharles street, in the city of Birmingham, county of Warwick, England,have invented certain new and useful Improvements in and Connected withClamping-Dogs, of which the following is a specification.

The invention provides the hereinafter described and claimedimprovements in and connected with clamping dogs or devices used formany purposes but generally used to hold work to beds, tables, and faceplates of machines, obviating the necessity of setting and of usingpack-up pieces.

Usually such a dog or device is a fiat or irregular shaped rigid piecethrough a slot in which a clamping bolt passes, and when using same itis invariably necessarv to packup with loose pieces of differentthicknesses. Such packing up is tedious, often very difficult, andalways mechanically bad, as no matter how arefully performed the chancesare that the position of the work will shift on final screwing up of theclamping bolt, freouently necessitating resetting.

The dog or device according to the invention embodies a rigidly builtpiece having three curved co-acting surfaces, two of which constitutefeet for gripping, and the other of which provides an elevatedbolt-pulling up abutment disposed between said feet. Looked at sidewisesaid dog or device is substantially arch shape, the feet of the archbeing the gripping feet, aforesaid, and the elevated surface the crownof the arch, or part adjacent forming the pulling up abutment. Thecurvings of the three surfaces extend sidewise of the dog or device saidsurfaces transversely being preferably without curvature. The curves ofthe feet provide convexity, but the curve of the abutment may be eitherconvex or concave. One foot may be longer than the other, but preferablythe curves thereof are alike as to radii. The bolt may pass freelythrough a slot in the dog or device arranged between the feet to engageeither a washer contacting the abutment or a block or piece rocking onthe abutment, said washer or piece provid ing flat surface for the nut fthe bolt to pull up against and being shaped at its contacting face tothe shape of the abutment.

The invention is represented by the accompanying drawing in which Figure1 is a side elevation and Fig. 2 a plan of the device.

The dog or device is composed of rigidly built pieces or sections 6 and6 each pr0- vided with three curved co-acting surfaces 7, g and it. Eachdog or device section is substantially arch-shape sidewise and thesurfaces 7 and 9 provide convex feet and the surface it a convex crownor pulling up abutment for the bolt (5. The curvings are sidewise onlyof the dog or device, said surfaces transversely having no curvature.

The curved surface it co-acting with the curved surfaces f and g isprovided by the lower halves of opposite transverse holes a and 0,formed through the dog or device body between the feet to providebearings for trunnions n 0 of a rocking bl0ck,'?, working in the slot Zand through a hole 2', in which a pulling up bolt is adapted to pass.This dog is built up of three pieces, the one the pivoted block 2' andthe others the two halves c c of the dog or device body, which halvesare put together at machined facings, c, and riveted up, at e c, withthe block between them so that the latter is always a permanent part ofthe dog or device.

The co-acting curved surfaces f, g and h are true ones, preferablymachined or ground so as not to have any irregularities, same beingtransversely parallel with each other. Said surfaces may be slightlyroughened or matted.

A dog or device according to the invention in addition to being selfsetting, and pulling up true in all conditions within its range ofthickness grip is free from slip, so that once the work is adjusted by apartial pulling up the final screwing up of the bolt will not cause anyshifting. Further said dog or device has no set positions beinginfinitely variable within its range of thicknessgrip and has noadjustment requiring skill.

Having now described our invention what we claim and desire to secure byLetters Patent is 1. A clamping dog comprising a rigid body structurehaving convex gripping feet,

and a block applied to said body structure between the feet and havingtrunnions engaging parts of the body structure and also provided with ahole therethrough for the reception of a bolt.

2. A clamping dog comprising a rigid body structure having convexgripping feet, and a block applied to said body structure between thefeet and having trunnions engaging parts of the body structure toproblock being retained in association as a part of the dog and havingan opening therethrough for the reception of a bolt.

3. A clamping dog comprising a rigid body structure having convexgripping feet vide a rocking movement for the block the CHARLES RALPHTOWNSEND. JOSEPH GEORGE SKINNER.

Witnesses GEO. FUERY, D. LEAKER.

